This image is a continuation of the last one. It shows the marked line (on masking tape) this line on the back and the front of the sheet lines up with the marks on the floor
The lower line (C) matches up with the mark that we placed at the door. All that is required is aligning the three markings to assure a square and well aligned finish.
It can be tricky for novices to continue a marking line on the reverse side of the roll.
So we use a simple method of making it accurate FOOLPROOF